/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_cmplx_mult_real_q15.c
*
* Description:	Q15 complex by real multiplication
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @addtogroup CmplxByRealMult
 * @{
 */


/**
 * @brief  Q15 complex-by-real multiplication
 * @param[in]  *pSrcCmplx points to the complex input vector
 * @param[in]  *pSrcReal points to the real input vector
 * @param[out]  *pCmplxDst points to the complex output vector
 * @param[in]  numSamples number of samples in each vector
 * @return none.
 *
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The function uses saturating arithmetic.
 * Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.
 */

void arm_cmplx_mult_real_q15(
    q15_t* pSrcCmplx,
    q15_t* pSrcReal,
    q15_t* pCmplxDst,
    uint32_t numSamples)
{
	q15_t in;                                      /* Temporary variable to store input value */

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */
	uint32_t blkCnt;                               /* loop counters */
	q31_t inA1, inA2;                              /* Temporary variables to hold input data */
	q31_t inB1;                                    /* Temporary variables to hold input data */
	q15_t out1, out2, out3, out4;                  /* Temporary variables to hold output data */
	q31_t mul1, mul2, mul3, mul4;                  /* Temporary variables to hold intermediate data */

	/* loop Unrolling */
	blkCnt = numSamples >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[i].            */
		/* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
		/* read complex number both real and imaginary from complex input buffer */
		inA1 = *__SIMD32(pSrcCmplx)++;
		/* read two real values at a time from real input buffer */
		inB1 = *__SIMD32(pSrcReal)++;
		/* read complex number both real and imaginary from complex input buffer */
		inA2 = *__SIMD32(pSrcCmplx)++;

		/* multiply complex number with real numbers */
#ifndef ARM_MATH_BIG_ENDIAN

		mul1 = (q31_t)((q15_t)(inA1) * (q15_t)(inB1));
		mul2 = (q31_t)((q15_t)(inA1 >> 16) * (q15_t)(inB1));
		mul3 = (q31_t)((q15_t)(inA2) * (q15_t)(inB1 >> 16));
		mul4 = (q31_t)((q15_t)(inA2 >> 16) * (q15_t)(inB1 >> 16));

#else

		mul2 = (q31_t)((q15_t)(inA1 >> 16) * (q15_t)(inB1 >> 16));
		mul1 = (q31_t)((q15_t) inA1 * (q15_t)(inB1 >> 16));
		mul4 = (q31_t)((q15_t)(inA2 >> 16) * (q15_t) inB1);
		mul3 = (q31_t)((q15_t) inA2 * (q15_t) inB1);

#endif //      #ifndef ARM_MATH_BIG_ENDIAN

		/* saturate the result */
		out1 = (q15_t) __SSAT(mul1 >> 15u, 16);
		out2 = (q15_t) __SSAT(mul2 >> 15u, 16);
		out3 = (q15_t) __SSAT(mul3 >> 15u, 16);
		out4 = (q15_t) __SSAT(mul4 >> 15u, 16);

		/* pack real and imaginary outputs and store them to destination */
		*__SIMD32(pCmplxDst)++ = __PKHBT(out1, out2, 16);
		*__SIMD32(pCmplxDst)++ = __PKHBT(out3, out4, 16);

		inA1 = *__SIMD32(pSrcCmplx)++;
		inB1 = *__SIMD32(pSrcReal)++;
		inA2 = *__SIMD32(pSrcCmplx)++;

#ifndef ARM_MATH_BIG_ENDIAN

		mul1 = (q31_t)((q15_t)(inA1) * (q15_t)(inB1));
		mul2 = (q31_t)((q15_t)(inA1 >> 16) * (q15_t)(inB1));
		mul3 = (q31_t)((q15_t)(inA2) * (q15_t)(inB1 >> 16));
		mul4 = (q31_t)((q15_t)(inA2 >> 16) * (q15_t)(inB1 >> 16));

#else

		mul2 = (q31_t)((q15_t)(inA1 >> 16) * (q15_t)(inB1 >> 16));
		mul1 = (q31_t)((q15_t) inA1 * (q15_t)(inB1 >> 16));
		mul4 = (q31_t)((q15_t)(inA2 >> 16) * (q15_t) inB1);
		mul3 = (q31_t)((q15_t) inA2 * (q15_t) inB1);

#endif //      #ifndef ARM_MATH_BIG_ENDIAN

		out1 = (q15_t) __SSAT(mul1 >> 15u, 16);
		out2 = (q15_t) __SSAT(mul2 >> 15u, 16);
		out3 = (q15_t) __SSAT(mul3 >> 15u, 16);
		out4 = (q15_t) __SSAT(mul4 >> 15u, 16);

		*__SIMD32(pCmplxDst)++ = __PKHBT(out1, out2, 16);
		*__SIMD32(pCmplxDst)++ = __PKHBT(out3, out4, 16);

		/* Decrement the numSamples loop counter */
		blkCnt--;
	}

	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x4u;

	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[i].            */
		/* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
		in = *pSrcReal++;
		/* store the result in the destination buffer. */
		*pCmplxDst++ =
		    (q15_t) __SSAT((((q31_t)(*pSrcCmplx++) * (in)) >> 15), 16);
		*pCmplxDst++ =
		    (q15_t) __SSAT((((q31_t)(*pSrcCmplx++) * (in)) >> 15), 16);

		/* Decrement the numSamples loop counter */
		blkCnt--;
	}

#else

	/* Run the below code for Cortex-M0 */

	while(numSamples > 0u) {
		/* realOut = realA * realB.            */
		/* imagOut = imagA * realB.                */
		in = *pSrcReal++;
		/* store the result in the destination buffer. */
		*pCmplxDst++ =
		    (q15_t) __SSAT((((q31_t)(*pSrcCmplx++) * (in)) >> 15), 16);
		*pCmplxDst++ =
		    (q15_t) __SSAT((((q31_t)(*pSrcCmplx++) * (in)) >> 15), 16);

		/* Decrement the numSamples loop counter */
		numSamples--;
	}

#endif /* #ifndef ARM_MATH_CM0 */

}

/**
 * @} end of CmplxByRealMult group
 */
